In this case probably Vulkan, as developers tend to use current computers which support Vulkan, which is faster and younger and has less overhead.

In other cases you probably want OpenGL because older GPUs don't support Vulkan and usually you want to include as many users as possible.

Neither is inherently better. It depends on what you need. Vulkan gives you more control which can be beneficial for advanced rendering techniques however comes at the cost of requiring more knowledge to use. OpenGL is simpler but generally has higher driver overhead.